1. Field of the Invention
This invention in general relates to the field of optical recording systems and media and, in particular, to storage media comprising integral near-field optics by which means a greater resolution and storage density is attained in the processes of writing to and reading from a recording layer.
2. Description of the Prior Art
The following technical articles and authors are relevant to the present application:
Newton
McCutchen
Kino
Gaudiana, R. A., et al, High Refractive Index Polymers, U.S. Pat. No. 5,132,430, Jul. 21, 1992, assigned to Polaroid.
Guerra, J. M., "Photon tunneling microscopy," in Proceedings from Surface Measurement and Characterization Meeting, Hamburg, SPIE Vol. 1009, pp. 254-262, 1988.
Guerra, J. M., "Photon tunneling microscope," Paper Summaries, SPSE 42nd Annual Conference, Boston, pp. 11-15, 1989.
Guerra, J. M., "Photon tunneling microscopy," Applied Optics, Vol. 29, No. 26, pp. 3741-3752, 1990.
Guerra, J. M., "Super-resolution through Diffraction-born Evanescent Waves," Appl. Phys. Lett. 66 (26), p. 3555. 1995.
Guerra, J. M., Plummer, W. T., Optical proximity imaging method and apparatus, U.S. Pat. No. 4,681,451, Jul. 21, 1987. Assigned to Polaroid Corp.
Cronin, D. V., Guerra, J. M., Sullivan, P. F., Mokry, P. A., Clark, P. P., Cocco, V. L., Data storage apparatus using optical servo tracks, U.S. Pat. No. 4,843,494, Jun. 27, 1989. Assigned to Polaroid Corp.
Guerra, J. M., Apparatus and Methods Employing Phase Control and Analysis of Evanescent Illumination for Imaging and Metrology of Subwavelength Lateral Surface Topography, U.S. Pat. No. 5,666,197, Sep. 9, 1997. Assigned to Polaroid Corp.
Guerra, J. M., Dark Field, Photon Tunneling Imaging System and Methods, Patent Allowed, June, 1997.
Guerra, J. M., Dark Field, Photon Tunneling Imaging Probes, Patent Allowed, June, 1997.
Guerra, J. M., Dark Field, Photon Tunneling Imaging System and Methods for Measuring Flying Height of Read/Write Heads, Patent Allowed, June, 1997.
Guerra, J. M., Dark Field, Photon Tunneling Imaging System and Methods for Optical Recording and Retrieval, Patent Pending.
Guerra, J. M., Apparatus and Methods for Providing Phase Controlled Evanescent Illumination, Patent Allowed.
Guerra, J. M., Phase Controlled Evanescent Field Systems and Methods for Optical Recording and Retrieval, Patent Allowed, Sept. 1997.
N. Bloembergen and C. H. Lee, Phys. Rev. Letters 19, 835 (1967).
Mirabella, F. M. Jr., and N. J. Harrick, Internal Reflection Spectroscopy: Review and Supplement, Harrick Scientific Corp., Ossining, N.Y. 1985.
A. Yariv, P. Yeh, Optical Waves in Crystals, John Wiley & Sons, N. Y., 1984. Bragg reflection p. 175. Gaussian beams, p. 25. Coupled mode theory, p. 177. Coupled mode theory of Bragg reflectors, p. 194. Form birefringence, p. 205. Electromagnetic surface waves, p. 209. Guided waves and integrated optics, p. 405. Surface plasmons, p. 489. Nonlinear optics, p. 504. Phase conjugate optics, p. 549.
A. Yariv, Optical Electronics, Holt, Rinehart and Winston, New York (1985). p. 88, Optical resonators, like their low-frequency, radio frequency, and microwave counterparts, are used primarily to build up large field intensities with moderate power inputs. A universal measure of this property is the quality factor Q of the resonator
P. Yeh, Introduction to Photorefractive Nonlinear Optics, John Wiley & Sons, Inc., New York, 1993.
A. Otto, "Excitation of nonradiative surface plasma waves by the method of frustrated total reflection," Z. Phys. (216), 398 (1968) and (219), 227 (1969).
Integrating optics and even micro-optics with a photo sensitive material is known in other applications not involving data storage, high spatial resolution, or even near-field integration. For example, Polavision.TM. film incorporated temporary lenticular lenses during production for the purpose of exposing color filter stripes on the emulsion. In the present state of the art, micro-optic elements may be added to a CCD imager so as to increase light efficiency by directing incident light away from the "dead" gate structures and into the photo-active areas. Many light detectors for light measurement or security devices use micro-optic arrays placed near the detector in order to increase the field of view of the detector.
In near-field optical applications, splitting off the total internal reflection (TIR) surface from the aplanatic immersion lens in an imaging objective and integrating it with the object to be viewed is taught in Guerra, Applied Optics 1990 and SPIE 1988, and in a flexible form (transducer) in Guerra, J. M., Flexible Transducers for Photon Tunneling Microscopes and Methods for Making and Using Same, U.S. Pat. No. 5,349,443, Sep. 20, 1994 assigned to Polaroid Corp., Guerra, J. M., Stereoscopic Photon Tunneling Microscope, U.S. Pat. No. 5,442,443, Aug. 15, 1995 assigned to Polaroid Corp, and Guerra, J. M., Method for Making Flexible Transducers for Use with Photon Tunneling Microscopes, U.S. Pat. No. 5,484,558, Jan. 16, 1996. Assigned to Polaroid Corp. Improvements and extensions of that split TIR concept are claimed and will be shown herein.
While the art describes a variety of optical storage media, there remains a need for improvements that offer advantages and capabilities not found in presently available instruments, and it is a primary object of this invention to provide such improvements.
It is another object of the invention to provide for a method of reading and writing utilizing evanescent field resolution.
It is another object of the invention to facilitate use of the near field to attain super-resolution in all axes for optical data storage reading, writing, erasing, where the data is stored as index changes (complex, may include absorption), polarization or other phase changes, topographic height changes, etc.
It is another object of the invention to fully utilize the whole-field optical capability for the purposes of: multi-tasking, multi-track encoding, faster data-transfer rates, faster random access time, more robust data through redundancy, elimination of radial actuator mechanisms, lower required disc rotation speed, higher track density through reduced cross talk in absence of Gaussian, robustness through redundancy, multi-channel encoding for higher data density, and multiple program simultaneous/interactive play.
It is another object of the invention to eliminate close-flying requirement of near-field head by miniaturizing, pluralizing, and integrating near-field optics to media.
It is another object of the invention to have better control over the flying and have a more stable near field that is integral with the medium by integrating near-field optics to the medium housing.
It is another object of the invention to improve the NA and signal-to-noise of propagating light optical data storage systems and media by integrating optical elements with the medium and/or the medium housing.
It is another object of the invention to integrate an internal reflection surface with a recording medium whereby the active layer can be protected by an overlying surface, such as a diamond-like coating, and whereby full factor of n.sup.2 is retained.
It is another object of the invention to provide removable, economic high-density, near-field media.
It is another object of the invention to provide removable, economic, high-density media with integrated optics for an increase in resolution and storage density by at least a factor of n with or without near-field or an immersion medium.
It is another object of the invention to provide a medium in which interaction of an integral near-field and the integral active recording, erasable, or ROM layer is either through frustration of TIR or attenuation of TIR.
It is another object of the invention to provide a medium in which integral micro-optics are used for optical discerning of data through interference, absorption, fluorescence, wavelength, size, height, or reflection differences.
It is another object of the invention to provide a medium in which the integrated optics are formed by gradient index in a substantially planar surface.
It is another object of the invention to provide a medium in which the integrated optics are holographic optical elements (HOEs).
It is another object of the invention to provide a medium in which the integrated optics can be molded in by injection, injection compression, or compression molding.
It is another object of the invention to provide a medium in which the integrated optics may be emplaced by means of embossing with heat or solvent.
It is another object of the invention to provide a medium in which the integrated optics can be internal, external, or part of an optical window in a protective housing.
It is another object of the invention to produce a near-field in the medium such that its characteristics can be precisely controlled.
It is another object of the invention to allow full use of the attributes of the near-field, including the vertical direction, where the stability of it being integral to the medium and not dependent on flying height variations and surface topography.
It is another object of the invention to facilitate use of the said stable integral evanescent field for multilevel, multi-layer, surface plasmon, resonant near-field, diffractive near-field, phase-resolved, wavelength (spectral, fluorescence) and/or other writing and reading techniques.
It is another object of the invention to provide for an increase in resolution by illuminating the micro-optic integrated medium either inside, outside, or at the critical angle, thereby using either propagating light or evanescent near-field.
It is another object of the invention to cause an increase in illumination intensity by: forming a smaller spot, and constructive interference in the standing wave that gives rise to the field.
It is another object of the invention to place the active recording surface or ROM surface internal to the medium for data protection.
It is another object of the invention to place the micro-optics either internal to the medium or integral to a housing.
It is another object of the invention to provide the prisms in a retro-reflective arrangement such that the photo-active layer resides on all TIR surfaces.
It is another object of the invention to fill micro-prism cavities with a high index polymer of about 1.9-2.1, or to planarize with a sol-gel process.
It is another object of the invention to provide a system that can be either epi-illuminated, dark-field illuminated, or phase-controlled illuminated.
It is another object of the invention to provide a small-format system for nomadic personal digital applications.
It is another object of the invention to provide an optical storage system that rivals or surpasses the data access speed and density of non-removable hard disc drives.
It is another object of the invention to provide integral optics that by virtue of their small size reduce aberrations normally introduced by substitution of a prism for an aplanatic sphere, while enjoying the full field of the prism.
It is another object of the invention to provide, in the case of the close packed array in the window of the cassette, optics with full axis of revolution, thereby regaining factor of n.sup.2.
It is another object of the invention to provide a plate, either flexible or rigid, having integral, internal, or external micro-optics in the form of a close-packed lens array that can be used for lithography and other energy delivery purposes, microscopic observation, metrology, or other in an oil-less immersion microscope that is low cost and regains large working distance, which can be used for interferometry as well as near-field depending on the NA.
It is another object of the invention to provide an integral medium that includes diffractive micro-optics which are much smaller than the wavelength and are planes in a crystal, thin film vertical layers, molecular scale polymers, phase gratings induced by holography or ion implantation or other, with the diffractive optics working alone or in tandem with refractive micro optics, said diffractive optics being 1, 2, or 3 dimensional, in order to produce evanescent fields with quasi-wavelengths much smaller than achievable with refractive index alone.
It is another object of the invention to provide two or more matched sets of diffractive optics, such that one acts as a reference and the other, when altered by light, creates interference between the two and a signal.
It is another object of the invention to encode the information from said diffractive structures in an analog form.
It is another object of the invention to encode the information from said diffractive structures in a digital form.
It is another object of the invention to provide media with integral optics that works well with staggered detector array for reduction or elimination of actuator, and subpixel resolution of data, and parallel processing.
It is another object of the invention to provide the foregoing features to any of a disc, a tape, or a photo-active layer.
It is another object of the invention to integrate light source, optics, diffraction grating, detector, into a flying head.
It is another object of the invention to take integration to its ultimate, an integrated optical chip or macro device in which is contained some or all of the following components: detector array, illumination array, total internal reflection interface, micro-optics, diffraction subwavelength optics, writeable erasable active layer, resonance layer structure, surface plasmon metal layer, phase resolution or shifting means, and so on for a true solid state storage device.
It is another object of the invention to use said integrated head in other applications, such as in lithography, in a print head in graphic arts, or as a medical sensor, or as a medical energy delivery device.
Other objects of the invention will be obvious, in part, and, in part, will become apparent when reading the detailed description to follow.